A loudspeaker, or simply a speaker, is an electroacoustic transducer that produces sound in response to an electrical audio input signal. The loudspeaker may include a cone supporting a voice coil electromagnet acting on a permanent magnet. Motion of the voice coil electromagnet relative to the permanent magnet causes the cone to move, thereby generating sound waves. Where accurate reproduction of sound is needed, multiple loudspeakers may be used, each reproducing a part of the audible frequency range. Loudspeakers are found in devices, such as radio and Television (TV) receivers, telephones, headphones, and many forms of audio devices.